Spiders can be found in every state across the United States, but only a handful of states have dangerously venomous spiders. The states with no poisonous spiders are Alaska, Maine, Hawaii, and New Hampshire.
Which states have poisonous spiders?
While the majority of spiders in the US are not considered medically significant, there are two types of spiders with potent venom that can cause serious medical issues in humans – the black widow spider and the brown recluse spider.
Black widow spiders are found in southern and western states, with the highest concentrations being in California, Texas, Florida, Georgia, and the Carolinas. Brown recluse spiders have a more midwestern distribution and are most prevalent in Missouri, Oklahoma, Kansas, Arkansas, Louisiana, and parts of Texas.
Outside of those two spiders, some other states have spider species that are venomous but rarely cause serious effects in humans, such as the hobo spider in the Pacific Northwest or the yellow sac spider found throughout the eastern half of the country.
Why do some states lack poisonous spiders?
There are a few key reasons why Alaska, Maine, Hawaii, and New Hampshire have no medically significant spider species:
- Climate – The cold climates found in Alaska, Maine, and New Hampshire are inhospitable to spiders like black widows and brown recluses that thrive in hot, humid conditions. Hawaii’s tropical environment also lacks the habitats these spiders prefer.
- Isolation – Hawaii’s geographic isolation in the middle of the Pacific Ocean prevents colonization by spider species from continents. Maine and Alaska also have a degree of geographic separation from spider populations.
- Lack of prey – Brown recluse spiders and other venomous species rely on large prey like insects and other arthropods, which are scarce in Alaska and Maine due to the colder climate.
Verifying the lack of poisonous spiders
While anecdotal reports indicate these four states do not have any dangerously venomous spiders, scientific verification requires thorough surveillance and documentation of species distributions. Some ways researchers can confirm poisonous spider-free status include:
- Field collection surveys – Scientists directly sampling spider populations across each state through trapping and specimen collection.
- Pest control reports – Reviewing data from exterminators on spider species found within homes and buildings.
- Bite symptoms – Monitoring bite symptoms at hospitals to detect signatures of black widows or recluses versus harmless species.
- Citizen science – Engaging the public to photograph and report spider sightings for experts to verify.
Combining multiple lines of evidence helps confirm the absence of any medically important spider species in Alaska, Hawaii, Maine or New Hampshire.
Spider diversity in the safe states
While lacking in poisonous spiders, these four states still host an array of unique and interesting spider species adapted to their environments.
Alaska
Over 400 spider species are found in Alaska, with some of the most common including:
- Jumping spiders – Distinctive for their jumping movement and excellent vision.
- Wolf spiders – Large, hairy spiders that actively hunt instead of using webs.
- Cellar spiders – Long-legged spiders making messy webs in houses.
- Crab spiders – Spiders that can camouflage into flowers.
Hawaii
Hawaii is home to over 175 endemic spider species, some unique ones being:
- Happy face spiders – Spiders with colorful markings resembling a smiling face on their abdomens.
- Cave spiders – Adapted to the dark lava tube caves across Hawaii’s islands.
- Orbweavers – Tropical spiders with colorful and intricate wheel-shaped webs.
- Jumping spiders – Quick-moving predators common in Hawaiin forests.
Maine
Maine has around 560 native spider species. Some interesting Maine spiders are:
- Fishing spiders – Large spiders adept at capturing fish and tadpoles.
- Bowl and doily spiders – Build impressive layered webs with a dome and mat.
- Raft spiders – Water spiders that can skate across the surface film.
- Sheetweb spiders – Construct flat, sheet-like webs in vegetation.
New Hampshire
Over 430 species of spider inhabit New Hampshire. A few examples include:
- Marbled orbweavers – Round spiders with colorful striped patterns on their bodies.
- Common house spiders – Small, messy web spiders living inside houses.
- Nursery web spiders – Active hunters sometimes mistaken for brown recluses.
- Banded garden spiders – Prominent black and yellow spiders in gardens.
Spider safety
While Alaska, Hawaii, Maine and New Hampshire are considered safe from venomous spiders, basic precautions should still be practiced:
- Carefully inspect areas before reaching or cleaning.
- Store firewood away from the home.
- Clean up clutter to discourage spider habitats.
- Seal cracks in foundations.
- Have children wash hands after playing outside.
- Shake out clothing, shoes, or equipment stored in sheds/garages before use.
Being aware of any spider bites and promptly seeking medical care is also recommended. But overall, residents and visitors to these four states can breathe a little easier knowing there are no poisonous spiders lurking.
Conclusion
Alaska, Hawaii, Maine, and New Hampshire are the only states that completely lack poisonous spider species like black widows and brown recluses that can cause dangerous bites. Their geographic isolation and cold climates prevent colonization by spiders needing warm conditions and large prey sources. Even without hazardous spiders, these states host hundreds of unique native spiders adapted to the local environments. While the lack of venomous spiders reduces risk, following sensible precautions around spiders can help further prevent bites.